How can they legally take his illegal guns if they did not have probable cause to take the guns without a warrant?
Because only legal guns can be taken.
No free man shall ever be debarred the use of arms. Thomas Jefferson (1776)
If you go into a store, with a gun, and rob it, you have forfeited your right to not get shot - Joe Deters, Hamilton County (Cincinnati) Prosecutor
I ask sir, what is the militia? It is the whole people except for a few politicians. - George Mason (father of the Bill of Rights and The Virginia Declaration of Rights)